Therapeutic cuff

ABSTRACT

A pressure cuff for medical therapeutic purposes is formed from a single walled, fluid impervious casing which is sealed to the body of a patient by one or more flexible, body-conforming, adherent flaps of thin film sheet material. Valves in the casing provide direct access to the body portion to be treated and allow maintenance of a controlled atmosphere around the body portion. A modification allows the use of both positive and negative pressures.

United States Patent [1 1 Spielberg Jan. 14, 1975 THERAPEUTIC CUFF [76]Inventor: Theodore E. Spielberg, 619

Washington St., Wellesley, Mass. 02181 [22] Filed: Feb. 15, 1973 [21]Appl. No.: 332,703

Related US. Application Data [63] Continuation-impart of Ser. No.321,313, Jan. 5,

1973, abandoned.

[52] US. Cl. 128/24 R, 128/64 [51] Int. Cl A6lh H00 [58] Field of Search128/24 R, DIG. 20, 60,

[56] References Cited UNITED STATES PATENTS 1,110,494 9/1914 Kellogg128/38 UX 1,399,095 12/1921 Webb 128/38 UX 1,629,108 5/1927 Lake 128/382,123,418 7/1938 Crosley et a1 128/300 3,094,983 6/1963 MacLeod 128/403,245,405 4/1966 Gardner.... l28/DlG. 20 3,303,841 2/1967 Dennis 128/24R 3,421,504 1/1969 Gibbons 128/299 X FOREIGN PATENTS OR APPLICATIONS449,304 9/1927 Germany 128/299 Primary Examiner-Lawrence W. TrappAttorney, Agent, or Firm-Ccsari & McKcnna [57] ABSTRACT A pressure cufffor medical therapeutic purposes is formed from a single walled, fluidimpervious casing which is sealed to the body of a patient by one ormore flexible, body-conforming, adherent flaps of thin film sheetmaterial. Valves in the casing provide direct access to the body portionto be treated and allow maintenance of a controlled atmosphere aroundthe body portion. A modification allows the use of both positive andnegative pressures.

12 Claims, 20 Drawing Figures "PATENTEDJANMIBYFJI I "3.859389 I SHEEHUF4 FlG.5

PATENTEDJANWBYFI 9.959.989

SHEET 2 BF 4 FATENTED 3,859,989

sum 30F 4 FIG. l2

THERAPEUTIC CUFF This application is a continuation-in-part of myabandoned U.S. Patent Application Ser. No. 321,313, filed Jan 5, I973.

BACKGROUND OF THE INVENTION A. Field of the Invention The inventionrelates to a pressure cuff, and comprises a single walled pressure cuffwith flexible, body conforming, adherent flaps of thin sheet materialforming a fluid-type seal between the cuff wall and the body portion towhich the cuff is connected.

B. Prior Art Patients confined to bed for extended periods of time arehighly susceptible to blood pooling in the lower extremities whichfrequently leads to the formation of blood clots in the veins. Toalleviate this, techniques have been developed for cyclically applyingpressure to the lower extremities to assist the venous return to theheart and thereby eliminate the pooling which leads to clotting. See,for example, U.S. Pat. No. 3,391,692 whichissued to me on July 9, 1968.

The cuff used in that technique is double-walled, the inner and outerwalls forming a fluid-impermeable chamber between them. This cuff isplaced around the body portion to be treated, and the chamber isalternately expanded and contracted in a cyclical manner to pump theblood in the extremities back toward the heart. A travelling wave is setup by the pumping cycle to thereby establish a preferential directionfor blood travel.

This cuff is highly beneficial in patient treatment, but it does havecertain disadvantages. Thus, the inner wall of such a cuff is inessentially continuous contact with the body surface being treated, andcan cause skin irritation if applied for extended periods of time.Further, moisture builds up at the skin surface under the cuff, thuscausing further patient discomfort over extended treatment intervals. Ofcourse, when medication is to be applied to the body portion beingtreated, or when it is to be inspected, the cuff must be removed. Andwhenever the body portion to be treated has surface lesions such ascaused by a wound or a burn which would be aggravated by direct cuffcontact or which would cause severe patient discomfort on such contact,the cuff cannot be used at all.

BRIEF DESCRIPTION OF THE INVENTION A. Objects of the InventionAccordingly, it is an object of the invention to provide an improvedpressure cuff.

Further, it is an object of the invention to provide a pressure cuffcharacterized by minimal body contact surface.

A further object of the invention is to provide a pressure cuff whichavoids moisture build-up at the skin surface.

Still another object of the invention is to provide a pressure cuffwhich allows the application of medication while maintaining pressure onthe part being treated.

A further object is to provide a pressure cuff which facilitates directinspection of the body portion being treated.

Yet another object of the invention is to provide a pressure cuff whichallows the maintenance of a controlled environment of the body surfacebeing treated. Still another object of the invention is to provide acuff for local hyperbaric treatment for cutaneous lesions such as burns.

. Still a further object of the invention is to provide a cuff which cansustain both positive and negative pressures.

B. Summary of the Invention As used herein, the term pressure cufdenotes a shell or casing for application over a body portion andhavingsealing means forming a pressurizable chamber between the casingand the body surface within the casing.

In accordance with the invention, l form a pressure cuff from asingle-walled casing of limited resilience having one or more flaps of athin, flexible, bodyconforming, adherent sheet material connected to theends thereof and forming a seal between the casing and a body portion tobe treated. The casing, as well as the end flaps, are fluid-tight, and,when properly positioned around the body portion to be treated, form achamber surrounding the body surface. A fluid such as air or other gasis admitted into, and vented from, this chamber by means of one or morevalves extending through the casing wall. These valves are connected,respectively, to a fluid source and a fluid sink. For example, one ofthe valves, serving as an inlet valve, may be connected to a pump forpressurizing the chamber from a fluid source, with the other valve,serving as an outlet valve, being connected in the return line of thepump or alternatively being vented to the atmosphere.

With the pressure cuff of the present invention, the body portion beingtreated is substantially free of contact with the casing and thus thereis no surface irritation engendered as the casing is periodicallypumped. The only direct contact is with the sealing flaps and these arehighly conformable to the body shape so as to cause minimal discomfort.This is especially advantageous for patients having wounds or skinlesions on the body portion which is to be pressure treated. Further,the moisture which forms at the body surface is continually purgedduring the pumping, and a further source of patient discomfort is thuseliminated. Moreover, the temperature of the pumping fluid can beregulated to the degree desired to best accomodate patient comfort andpromote healing. Indeed, medication in desired amounts and at thedesired intervals may be introduced at the chamber by means of thepumping system and this medication is brought into direct contact withthe body surface being treated.

The wall of the casing, as noted above, is made from a material oflimited resilience. For example, the casing may be formed from a clothwall having an inner coating or lining of rubber or plastic to renderthe walls substantially fluid-impermeable; this construction is the typeused in conventional blood pressure cuffs. Alternatively, the casingwall may be of a completely rigid material such as molded, hard plasticor even light metal such as aluminum. Preferably, however, whether rigidor of limited flexibility, the casing wall is advantageously formed froma translucent material which facilitates inspection of the body sectionwithout removing the pressure cuff, and one of the many plastics willthus frequently be found best.

The end flaps which form the seal between the casing and the bodyportion being treated are formed from a thin, highly flexible,deformable, body conforming adherent sheet. Thin sheets of numerousmaterials, including various rubbers and plastics among others, have thedesired body-conforming and body-adherent characteristics. The adherencemay be primarily mechanical in nature (due to surface roughness andsimilar factors), or primarily physio-chemical in nature (e.g.,electrostatic properties caused by molecular polarization) or both.

The thickness of each flap is of the order of a few mils (thousandths ofan inch) to ensure snug conformity with the body section. The flaps,which are securely fastened to one end of the casing cuff, are ofsufficient length to extend a few inches from the point of attachmentand along the body surface.

Because of their body-conforming characteristic, the flaps form a sealwith the body over a large area and thus do not create excessivelocalized and flowrestricting pressure such as may be created by anelastic type restrictive seal.

When the cuff is applied to a body portion, the flaps are foldedinwardly of the casing and the chamber formed by the casing and theflaps is pressurized. The air pressure in the chamber pushes the freeends of the flaps both outwardly and against the body portion over theirlength; the frictional and/or electrostatic forces between the flaps andthe surface of the body portion resist the outward thrust on the flapsand hold them and the casing snugly inplace. When the chamber is thusinflated, the casing is held away from the body surface and thus doesnot chafe or otherwise irritate it.

Valves extending through the casing allow pressurization of the chamber.This pressurization may be cyconditions the fluid (e.g., by removingmoisture from it) and medicates it as desired.

As long as the cuff is to be used with pressures above atmosphericpressure a single sealing flap around the enclosed body portion isadequate. For a cuff which must accomodate both positive and negativepressures, however, a modified form of seal is provided. The modifiedseal has two parts, a first of which is identical to the single(positive-pressure) seal described above and a second of which is anegative pressure seal formed by a resilient sheet attached on all sidesto the interior wall of the casing adjacent the body portion with whicha seal is to be formed and forming a closed cell containing air or otherexpansible fluid. The cell normally contributes little, if anything, tosealing the cuff when the cuff is pressurized to a positive (aboveatmospheric) pressure, but expands and seals the cuff to the bodyDETAILED DESCRIPTION OF THE INVENTION The foregoing and other andfurther objects and features of the invention will be more readilyunderstood from the following detailed description, when taken inconjunction with the accompanying drawings, in which:

FIG 1 is a view in perspective of one form of cuff in accordance withthe present invention and prior to its application to a body section;

FIG. 2 is a view in perspective of the cuff of FIG. I applied to a legand having a pumping and fluid treatment system connected to it;

FIG. 3 is a vertical side sectional view of the cuff of FIG. 2 takenalong the lines 3-3 of FIG. 2;

FIG. 4 is a side view of another sectional embodiment of my inventionshowing a single walled pressure cuff having only one open end;

FIG. 5 is an end sectional view taken along the lines 5-5 of FIG. 4;

FIG. 6 is a vertical side sectional view of another embodiment of theinvention utilizing a rigid shell with internal support and showing analternative construction for attaching the sealing flaps;

FIG. 7 is an end sectional view along the lines 7-7 of FIG. 6;

FIG. 8 is a vertical side sectional view of still another embodiment ofthe invention showing a further alternative constr'uction for the endflaps;

FIG. 9 is an end sectional view along the lines 9-9 of FIG. 8;

FIG. 10 is a vertical side sectional view of still another embodiment ofthe invention showing yet another construction for attaching the endflaps;

FIG. 11 is an end sectional view along the lines 11-11 of FIG. 10;

FIG. 12 is a sketch of another form of cuff of the present inventionwith portions broken away for clarity, illustrating its use in providinghyperbaric treatment of the upper body, including the head;

FIG; 13 is a view in perspective of a mouth mask constructed inaccordance with the present invention; and

FIG. 14 is a view in perspective of the mask in FIG. 12 as applied tothe mouth of the patient.

F IG. ISA-C are side sectional views of an alternative cuff inaccordance with the present invention which accomodates both positiveand negative cuff pressure;

FIG. ISD is a side sectional view of an alternative embodiment of thecuff of FIGS. lSA-C.

FIG. 16 is a side sectional view of another embodiment of the cuff shownin FIG. 15; and

FIG. 17 is a side sectional view of still another embodiment of the cuffshown in FIG. 15.

In FIG. 1, one embodiment of a pressure cuff in accordance with thepresent invention that is especially useful for application to the lowerextremities has a single-walled, outer cylindrical casing 10 to whichare secured end flaps l2 and 14 respectively. The casing is preferablyformed from a translucent plastic material such as vinyl, while theflaps 12 and 14 are formed from a thin, flexible, body conforming,adherent sheet of material such as rubber or a silica-filled vinyl sheet(the silica providing frictional properties). The length of the flaps inthe longitudinal direction-(i.e., in a direction parallel to the axis ofthe cylindrical cuff 10) should be of the order of 3 to 4 inches toprovide sufficient sealing surface for contact with the body portion.Notches 16 may be formed around the periphery of the outer ends of theflaps 14 to assist in conforming the flaps to the smaller diameter ofthe body portion which they are to encompass. Valves l8 and 20 extendthrough the wall 12 to the interior of the cuff.

In FIG. 2, the cuff 10 of FIG. 1 is shown applied to the lower leg of apatent. The cuff completely encompasses a portion of the leg, and theflaps 14 are folded inwardly of the casing 12 and snugly fold around theleg within the cuff. The cuff forms a chamber 22 which is sealedfluid-tight by the flaps 14, 16 when the chamber is pressurized. Fluidis admitted to this chamber through valves 18 and 20 which are connectedto a pumping source 24 through lines 26 and 28. Valves 30 and 32respectively, are positioned in these lines. When the valves 30 and 32are closed, the pumping source 24 provides fluid under pressure to theinterior of the cuff in a closed loop from the source 24 through thevalve 30 and line 26, to the cuff l0, thence back through the line 28and valve 32 to the pumping source 22. Valve 32 is a three positionvalve which may alternatively be positioned to vent the fluid from thecasing 22.

In addition to providing pressurized fluid to the cuff 10, the pumpingsource 24 may condition the fluid it supplies. Thus, for example, thesource 24 may contain moisture extraction apparatus (not shown) toremove excessive moisture from the fluid supply to the cuff.Alternatively, it may supply moisture to the body segment within thecuff when the moisture level is too low. Additionally, it may beconnected to receive medication from a source 34 and apply it incontrolled and timed amounts to the body segment in cuff 10. Thus, theenvironment of the body segment within the cuff 10 may be preciselycontrolled.

FIG. 3 is a cross-section of the cuff 10 of FIG. 2. As shown in FIG. 3,those portions of the flap 14 nearest the casing 12 are bowed outwardlyby the pressure within the cuff, while the ends of the flaps farthestfrom the casing are pushed against the body portions by the pressurewithin the cuff 10 and snugly conform to the body portion at the areasof contact. The snug adherence between the flaps 14 and the body portionprevent the flaps from being pushed completely out of the cuff. Thus,they form effective seals with the leg and allow pressurization of thechamber 22.

In FIG. 4, an alternative embodiment of the invention is shown in whichthe pressure cuff is formed from a rigid or semi-flexible casing 40having only a single open end 42 sealed by a thin, flexible,circumferentially extending, body-conforming adherent flap 44 andforming a chamber 46 encompassing the leg. This form of pressure cuff isespecially useful in counterpulsation treatment. Again, the flap 44 isseveral inches in length to allow sufflcient surface contact area withthe body portion to thereby form an effective seal. Valves 48 and 50extending through the casing 40 provide a means of admitting fluid tothe chamber 46 and discharging it from that chamber, respectively. Afoot rest 52 is desirably provided to elevate the patients leg but maybe pushed out of the way if desired. The cuff is sufficiently large toenable the patient to move his legs to comfortable positions as desired.Note that both legs may be enclosed within the casing simultaneously sothat both can be subjected to even pressure without squeezing themtogether.

Turning now to FIGS. 6 and 7, the pressure cuff 60 shown there has arigid casing 62 terminating at one end in an inwardly turned generallycircular flange 64. A thin, flexible, body-conforming, adherent flap ofsheet material 66 is firmly secured to this flange, (for example, byadhesive or by thermoforming techniques) and extends inwardly severalinches within the casing and in contact with the surface of the legpositioned within the casings 62. The casing forms a chamber 68 which issealed by the flaps 66 against fluid leakage. Pressurizing fluid isadmitted to the chamber by means of a valve 70 and is discharged fromthe chamber by means ofa valve 72. A sling 74 may be attached to thecasing for providing a rest for a limb within it.

In FIGS. 8 and 9, a pressure cuff has a casing 82 with a flanged,inwardly turned end wall portion 84 at one end thereof. A cylindricalring 86 of dimensions somewhat larger than the maximum cross section ofthe body section being treated is attached to the end wall 84 and athin, flexible, body conforming, adherent flap 88 connected to the ring86. Ring 86 lightly engages the limb positioned within it. Its purposeis to minimize any outward bowing of the flap 88 and thus this ring neednot itself provide the sealing action, the latter being providedcompletely, or nearly completely, by the flap 88. The casing 82 forms achamber 90 which is sealed by flap 88. The chamber is pressurized anddepressurized by means of valves 92 and 94, respectively. A foot rest 96may be provided within the casing 82 for the patients comfort.

In FIGS. 10 and 11, a thin, flexible, circumferentially extending,body-conforming, adherent flap 100 extends between anend segment of acasing 102 and a cylindrical ring 104. The ring 104 is of sufficientdiameter to allow the body segment to be treated to be extended throughit without discomfort, and it serves to anchor the flap 100 againstoutward bowing when the chamber 106 within the casing is pressurized.The ring 104 need not itself provide any sealing action and thus neednot be pressed tightly against the body section. The casing 102 forms apressure chamber 106 which is sealed by the flap 100. Valves 108 and 110are provided for pressurizing and depressurizing the chamber 106,respectively. A rest 112 may be provided for comfort of the patient.

FIG. 12 shows a form of pressure cuff suitable for hyperbaric treatmentof patients with respiratory problems. In this instance the cuff takesthe form of a preferably rigid semi-cylindrical casing 110 with roundedtop suspended on the shoulders of the patient by means of straps 112 andforming a pressure chamber 114. The casing is, of course, preferably ofa translucent meterial. A sealing flap 116 of thin, flexible,bodyconforming, adherent material such as saran extends between in-turned edges 118 of casing 110 and a ring 120 of sufficient diameter of fitover the patients head. The flap 116 is snugly engaged against thepatients chest when the chamber 114 is pressurized. Valves 122 and 124allow chamber 114 to be pressurized and depressurized, respectively.

In FIG. 12 a mask 128 adapted to fit over a patients mouth is shown. Themask has a generally oval crosssection and is formed from an outersemi-flexible or rigid casing 130 having a thin, flexible,bodyconforming, adherent flap 132 attached to its rim. A pair of valves134, 136 extend through the casing 130 for pressurizing anddepressurizing the interior thereof when the casing is applied againstthe mouth of the patient. A pair of straps 136, 138 are also attached tothe casing 130 for holding the casing against the mouth of the patientas shown in FIG. 14. When the cuff is applied to the patient, the flap132 is extended inwardly toward the housing 130. When the interior ofthe housing is pressurized, the flap is pushed snugly against thepatients skin and forms a fluid tight seal with it.

The pressure cuff may in the same manner be advantageously used inhyperbaric treatment of the eye, since it allows free eye movementbeneath it. It also may beneficially be applied as an ostomy or stomacover (as in a colostomy, urostomy or iliostomy, and contains gasrelease since it forms a tighter seal as the pressure increases.

In certain types of treatment it is desirable to provide for positive aswell as negative pressures within the cuff. For example, in a type oftherapy known as counterpulsation therapy, one cyclically andalternately applies positive and negative pressures to a body portion toassist the pumping action of the heart and thereby relieve strains onthe heart caused by its normal pumping action. The cuff of the presentinvention is especially suited to this type of therapy since it offersgreater comfort to the patient, and the patient may therefore be placedin it for treatment for extended periods of time without unduediscomfort. However, in order to accommodate negative as well aspositive pressures, the sealing flap illustrated and described inconnection with FIGS. 1 through 14 must be modified.

Such a modified form of seal is shown in FIGS. ISA-15C, together with amodified form of cuff which is especially suited to applying alternatepositive and negative pressures toa patient. The particular type of cuffshown has a single open end and is specifically adapted tocounterpulsation treatment, but it will be understoood that a cuff ofthe type shown in FIGS. 1-3 and open at both ends is equally welladapted to the modified seal now to be described. As shown in FIGS.ISA-15C, a cuff l is formed from a relatively inflexible or even rigidcasing 112 of sufficient size to confortably accommodate the bodyportion to be treated. One end of the casing 112 is closed'by aresilient membrane 114 to form a chamber 115 interior to the casing. Themembrane is connected to a shaft 116 through an adapter 118. The adapter118 is firmly attached to the membrane 114 and pivotally connects theshaft to the membrane. A crank arm 120 is pivotally connected to shaft116 at one end thereof and is connected at the other end to a pin 122 onthe outer perimeter of a wheel 124. The wheel 124 is rotated by a motor126. A guide block 128 has a groove 130 in which a follower block 132rides. The block 132 is connected to the pivot between arms 116 and 120.

A body portion 134 such as the lower torso of a patient, is placedwithin the casing 1 12. As was previously the case, a footrest 136 maybe provided in the casing for the patients comfort. A thin, flexible,bodyconforming adherent flap 140 of sheet material having one edgefirmly attached to an end 112a of the casing 112 is positioned to form afluid-tight seal with the patients body. The flap extendscircumferentially around the patients body as was the case in FIGS. 1thorugh 14 to thereby form an airtight seal with it. A flexible,resilient flap 142 also extends circumferentially around the patientsbody at the open end of the cuff 110. It is sealed to the casing 112 atboth its edges to form a closed cell 144 containing an expansible gassuch as air. A wall 112a of the casing extends into the casing adjacentthe flap 142.

As illustrated in FIG. A, the chamber 115 is initially at atmosphericpressure. For purposes of illustration', it will be assumed that thecell 144 was closed off under atmospheric pressure so that the pressurewithin the cell as illustrated in FIG. 15A is also atmospheric.

The flap 140 lies against the body and conforms lightly to its contour.The flap 142 rests lightly against the body at the upper portionthereof, but is drawh away from the body by its own weight at the lowerportion thereof. In this position, the pressure in the chamber 115 is inequalibriurn with the pressure outside this chamber and neither the flap140 nor the flap I42 need provide any sealing action.

Turning now to FIG. 158, as the motor 126 turns the wheel 124, the arm116 moves to the right and drives the adapter 118 to the right. Thismoves the membrane 114 inwardly into the chamber 115 and diminishes thefree volume of this chamber, thereby causing a pressure rise within it.The seal 140 conforms more snugly to the body portion which itencircles, and prevents escape of air from the chamber 115. At the sametime, the flap 142 has a net pressure exerted on it from the chamber 115and thus the volume of the cell 144 diminishes, while the pressureinside the cell increases. No sealing action is provided by the flap 142in this condition; instead the entire sealing is provided by the flap140.

As the motor 126 continues to rotate the wheel 124, the shaft 116reverses its motion and moves to the left, thus drawing the membrane 114outwardly of the chamber 115. This increases the effective volume of thechamber and thereby diminishes its pressure. When this occurs, air wouldnormally move into the chamber 115 under the flap 140 and thereby breakthe seal otherwise provided by this flap. However, this is prevented bythe seal 142 which, in response to the drop in pressure in chamber-115,expands outwardly, thereby increasing the volume of chamber 144, anddiminishing its pressure. In expanding outwardly, it presses against theflap 140 and pushes this flap firmly against the body portion 134, thusmaintaining the'effective seal between flap 140 and the body portion134. The wall 112a ensures that the flap 142 expands against the bodysurface. Thus, the chamber can be dropped to a pressure belowatmospheric (negative pressure), without leakage of air into it from theoutside of the cuff.

As the pressure in the chamber is cycled between sub-atmosphericpressure and super-atmospheric pressure, therefore, the seals 142 andalternately become effective to provide the desired sealing action. Inno event, however, is the maximum sealing pressure greater than eitheratmospheric pressure or the maximum pressure in the chamber 115.Further, this pressure is maintained over a substantial area and is notconfined to a thin, ring-like section which may cause patientdiscomfort.

An alternative method of attaching flap 142 is shown in FIG. 15D. thereshown, one edge of this flap is attached directly to an inner edge ofwall 1 12a; the opposite edge of this flap is attached to the rear wallll2b of the casing. The flap 142 forms closed chamber 144a with thewalls 112a and 11%. This chamber expands and contracts in the mannerdescribed in connection with FIGS. lSA-C to allow sealing of the opencasing end under both positive and negative pressure conditions.

It is, of course, possible to omit the sealing flap 140 entirely andinstead use only the flap 142 which forms and expansible chamber. Insuch a case, the flap 142 must effectuate a seal under both positive andnegative pressure conditions. This is accomplished by first placing thebody portion to be treated in the casing with the chamber 144 formed bythe flap 142 collapsed to per mit this. This chamber is then pressurizedto a pressure in excess of atmospheric pressure and of sufficientmagnitude that it can maintain a seal with the body portion even whenthe chamber 115 is pressurized; it will thus also maintain a seal at orbelow atmospheric pressure. This type of seal may also replace the seal14 shown in FIGS. 1-3. However, this type of seal exerts pressure aboveatmospheric pressure at all times, and thus will in general not be ascomfortable as the seals shown in FIGS. 1 and 15 which comprise an openflap with a free end (FIGS. l14) and both an open flap with a free endand a closed flap forming an expansible chamber.

Various arrangements may also be used to provide the cyclic pressire forcounterpulsation and other types of treatment. Two such alternatives areshown in FIGS. 16 and 17, respectively. In FIG. 16, the flexiblemembrane 114 is replaced with a bellows 150 which is fluidtight sealedat an end 150a and which communicates with a chamber 115 at the otherend 15%. As was the case with the membrane 114, the bellows 150 isreciprocated by a rod 116 to alternately raise and lower the pressure inthe chamber 115 by changing the effective volume as the rod 116reciprocates.

In FIG. 17, the casing 112 terminates in an enlarged segment 1126 whichis sealed fluid-tight by a correspondingly enlarged diaphragm 114a. Thisprovides an enlarged chamber 115A whose effective volume is changed asrod 116 is reciprocated. By providing a chamber 115A of broad diameterbut narrow width, the combined effective volume of chambers 115 and 115A(and thus the fluid pressure in these chambers) can be changed quiterapidly and over a wide range.

From the foregoing, it will be seen that I have provided an improvedpressure cuff. The cuff is single walled and is readily supported awayfrom the surface of the body portion being treated so as to prevent thediscomfort normally caused by frictional contact of the cuff with thepatient. A simple yet effective seal is formed on the cuff by means ofone or more flaps of a flexible, thin, body-conforming, adherent sheetof material which snugly conforms to the body portion when the interiorof the casing is pressurized. The sealing force is distributed over alarge area in this type of seal, and this eliminates any excessivelocalized sealing pressure which would otherwise impede bloodcirculation in a patients body. The single walled casing allows directaccess of the pressurizing fluid to the body surface and thus provides aconvenient means for medicating this surface or otherwise controllingthe atmosphere surrounding it. By utilizing a translucent material forthe casing itself, continuous visual access to the surface being treatedis provided.

The thickness of the sealing material is, of course, dependent on thematerial being used and the pressures to be applied, as well as theduration and repetition rate of the pressure application. In general,the seal must be thick enough to withstand the applied pressure and notdistort excessively under it, and yet must be thin enough to snuglyconform to the body section to which it is applied to thereby form afluidtight seal. For plastic materials such as a vinyl, sheets of lessthan 0.005 inches thick will be found useful, while with other materialsthis thickness may be greater or less.

It may sometimes be found desirable to further improve both the adherentcharacteristics of the sealing material and its sealing ability byapplying a small amount of viscous paste to the interface between thesealing flaps and the body portion. This is especially the case when thesealing material has poor (low) frictional characteristics.

It will be understood that the foregoing material is illustrative onlyand that various modifications may be made to the invention as describedherein without departing from the spirit or the scope of the invention,the scope of the invention being defined in the claims.

Having illustrated and described my invention, I claim:

1. A therapeutic cuff for an animal body comprising A. a relativelyinflexible casing for positioning over a body portion and forming achamber therewith,

B. at least one thin, flexible, body conforming, adherent, elongatedsheet having a first end thereof circumferentially attached to saidcasing and having a second end thereof extending radially inwardly fromsaid casing for engagement along a substantial area, intermediate saidends, with a body positioned within said casing to thereby form acircumferentially extending fluid tight sealing flap surrounding saidbody portion and isolating the interior of said chamber from theexterior thereof, the diameter of said flap at its ends and all portionstherebetween being greater than that of the body portion it contactswhereby said flap exerts substantially no force of its own against saidbody portion,

C. means forming a circumferentially extending closed auxiliary chamberon an interior wall of said casing and having a deformable wall incontact with a surface of said flap opposite the surface in contact withsaid body portion, said chamber being pressurized to substantiallyatmospheric pressure to thereby exert minimal force against said flapand said body portion when the pressure within said casing is greaterthan atmospheric pressure and to exert a sealing force against said flapand body portion' when the pressure in said chamber is less thanatmospheric, and

D. means on said cuff for pressurizing said chamber.

2. A therapeutic cuff in accordance with claim I in which said sheetincreasingly frictionally adheres to said body portion when said chamberis pressurized.

3. A therapeutic cuff in accordance with claim 1 in which said sheet issufficiently thin to snugly conform to a body contour it engages andsufficiently thick to withstand rupture by the chamber pressure.

4. A therapeutic cuff in accordance with claim 3 in which said sheet isformed of rubber.

5. A therapeutic cuff in accordance with claim 3 in which said sheet isformed of plastic.

6. A therapeutic cuff in accordance with claim 3 in which said sheet isformed of a plastic that is treated to increase its frictionalengagement with a body surface it contacts.

7. A therapeutic cuff in accordance with claim 3 in which a viscouspaste'is applied between the bodyconforming sheet and the body portionto which it is to be sealed to thereby increase adherence between saidbody portion and said sheet and further increase the security of theseal.

8. A therapeutic cuff in accordance with claim 1 in which said casing iscylindrical in shape and is adapted to completely encompass said bodyportion.

9. A therapeutic cuff for an animal body, said cuff comprising A. acasing for forming a hollow air chamber surrounding a body portion to betreated,

B. means for extending between said casing and said body portion forsealing said chamber fluid-tight; and

C. means forming a flexible wall in said casing and of substantiallylarger cross section than the chamber containing the body portion to betreated and movable inwardly and outwardly of said chamber to wardly andoutwardly of said chamber.

1. A therapeutic cuff for an animal body comprising A. a relativelyinflexible casing for positioning over a body portion and forming achamber therewith, B. at least one thin, flexible, body conforming,adherent, elongated sheet having a first end thereof circumferentiallyattached to said casing and having a second end thereof extendingradially inwardly from said casing for engagement along a substantialarea, intermediate said ends, with a body positioned within said casingto thereby form a circumferentially extending fluid tight sealing flapsurrounding said body portion and isolating the interior of said chamberfrom the exterior thereof, the diameter of said flap at its ends and allportions therebetween being greater than that of the body portion itcontacts whereby said flap exerts substantially no force of its ownagainst said body portion, C. means forming a circumferentiallyextending closed auxiliary chamber on an interior wall of said casingand having a deformable wall in contact with a surface of said flapopposite the surface in contact with said body portion, said chamberbeing pressurized to substantially atmospheric pressure to thereby exertminimal force against said flap and said body portion when the pressurewithin said casing is greater than atmospheric pressure and to exert asealing force against said flap and body portion when the pressure insaid chamber is less than atmospheric, and D. means on said cuff forpressurizing said chamber.
 2. A therapeutic cuff in accordance withclaim 1 in which said sheet increasingly frictionally adheres to saidbody portion when said chamber is pressurized.
 3. A therapeutic cuff inaccordance with claim 1 in which said sheet is sufficiently thin tosnugly conform to a body contour it engages and sufficiently thick towithstand rupture by the chamber pressure.
 4. A therapeutic cuff inaccordance with claim 3 in which said sheet is formed of rubber.
 5. Atherapeutic cuff in accordance with claim 3 in which said sheet isformed of plastic.
 6. A therapeutic cuff in accordance with claim 3 inwhich said sheet is formed of a plastic that is treated to increase itsfrictional engagement with a body surface it contacts.
 7. A therapeuticcuff in accordance with claim 3 in which a viscous paste is appliedbetween the body-conforming sheet and the body portion to which it is tobe sealed to thereby increase adherence between said body portion andsaid sheet and further increase the security of the seal.
 8. Atherapeutic cuff in accordance with claim 1 in which said casing iscylindrical in shape and is adapted to completely encompass said bodyportion.
 9. A therapeutic cuff for an animal body, said cuff comprisingA. a casing for forming a hollow air chamber surrounding a body portionto be treated, B. means for extending between said casing and said bodyportion for sealing said chamber fluid-tight; and C. means forming aflexible wall in said casing and of substantially larger cross sectionthan the chamber containing the body portion to be treated and movableinwardly and outwardly of said chamber to thereby change the pressuretherein at a rate greater than that achievable by flexible walls ofcross sectioN comparable to that of the chamber containing the bodyportion to be treated.
 10. A therapeutic cuff according to claim 9 inwhich said flexible wall comprises a resilient membrane diaphragm.
 11. Atherapeutic cuff according to claim 9 in which said flexible wall is inthe form of a bellows.
 12. A therapeutic cuff according to claim 9 whichincludes reciprocating means for moving said wall inwardly and outwardlyof said chamber.